1. 5687 based simple preamp Basic layout DIY Paradise 9 January 2003

2. 6X45687 Schematic Signal circuitry courtesy of vt4c@hotmail.com

3. Input RCA jack Output RCA jack IEC socket Power transformer 50+50uF/ 500V electrolytic capacitor 6X4 5687 Stereo volume pot Chassis Layout Top View

4. Output RCA jack Input RCA jack IEC socket 50+50uF/ 500V electrolytic capacitor 6X4 5687 Stereo volume pot 30H chokes Chassis Layout Bottom View Few points to note here. Power circuitry is kept at center. Signal comes in from the input RCA jack, goes to volume pot, then tube, then routes to output RCA jack. Coloured wavy line shows signal path. The purpose of doing the layout is to avoid stray flux (from transformer, chokes) from coupling into your signal and also to ensure components are not too cramped together to the extent that there isn't enough ventilation.

5. The following wiring diagrams are meant to aid you in the sequence in wiring this preamp. Of course, you can do it some other way. Any other way, actually. Please note that layout of components is not to scale, so when you plan your chassis, don’t simply “follow” what you see here. Remember basic rules still apply: keep signal wires far away from filament wires transformer, chokes and tube rectifier. cross only at 90 degrees. twist tightly the heater wires, place close to chassis. maintain star ground. SAFETY FIRST: REMEMBER TO SOLDER IN BLEEDER RESISTOR! REMEMBER TO “EARTH THE CHASSIS”! You “earth the chassis” by wiring Earth of IEC socket to chassis, through a nut. THEN confirm the resistance between Earth of IEC and chassis is as close to zero as possible.

6. 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 9 Gnd Out In Unused Alps stereo pot Ground layout Input RCA jack short to chassis Output RCA jack insulated from chassis 50+50uF 500V 6X4 5687 Using tube socket spigot as ground

7. 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 9 Gnd Out In Unused Alps stereo pot 3.15-0-3.15V Wiring of heaters

8. 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 9 Gnd Out In Unused Alps stereo pot 350-0-350V 30H choke Wiring of power supply 270kohm 2W Tap B+ from here Bleeder resistor. Very important!!!!!

9. 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 9 Gnd Out In Unused Alps stereo pot 350-0-350V 30H choke Wiring of In/Out circuitry 0.47uF 1 Mohm L / R OutputL / R Input

10. 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 9 Gnd Out In Unused Alps stereo pot 3.15-0-3.15V 350-0-350V 30H choke 3.15-0-3.15V Wiring of signal circuitry 10kohm 470ohm paralleld with 470uF L / R InputL / R Output